Sulphurized petroleum cutting oils



Patented Mar. 2 9, 1938 V I 2,1

UNITED STATES PATENT- OFFICE SULPHUBIZED PETROLEUM OUTING OILS Irving E. Muskat, Pittsburgh, Pa., assignor to Gull Research & Development Company, a corporation of. Delaware No Drawing. Application September 12, 1935, Serial No. 40,347

. 5 Claims. (Cl. 87-9) This invention relates to sulphurized petroleum gards lubricating and cooling action in cutting cutting oils; and it comprises a process of malnng work and the chlorinated petroleum oils have the from petroleum oils a stable sulphurized oil base serious disadvantage of decomposing during use of high sulphur content from which a lubricating with evolution of corrosive gases containing HCl.

5 and-cooling oil may be compounded for use in sulphurized petroleum cutting oils have been machining metal parts and in cutting metal obmade in the form of emulsions of sulphur in oil. jects in general, said process comprising heating The tendency of these emulsions to break has not a petroleum distillate containing unsaturated been entirely overcome and separation of sulphur hydrocarbons with relatively large amountsof from the emulsions has been a common disadelemental sulphur until the sulphur disappears vantage. In making sulphurized petroleum bases as such and distilling the sulphurized oil at a in which sulphuris held in chemical combination moderate temperature so as to remove unsul with the petroleum hydrocarbons, the proportion phurized hydrocarbons; and it further comprises of sulphur held in combination has been small a sulphurized oil base of low viscosity used for and use of these bases with compounding oils the preparation of cutting oils and composed of a has been necessarily limited by their low sulphur stable liquid union of unsaturated petroleum hycontent. e drocarbons and sulphur in a proportion from In the present invention I have succeeded in 15 to 40 per cent of the whole; all as more fully forming a stable liquid union of petroleum hyhereinafter set forth and as claimed. drocarbons and sulphur in proportions such that Cutting oils, that is, oils used for lubricating the sulphur content of the sulphurized base is 20 machine tools in the cutting of metals of all high enough to permit mixture of the sulphmkinds, have become important in connection with ized base with low grade oils in dilutions of the the use of high speed machine tools. It is an order of 10 .or 20 to 1 or even higher, without achieved object of the present invention to proseparation of sulphur and without loss of the vide a cutting oil made from petroleum and havadhesive or wetting properties of the diluted v 25 ing the lubricating action in the cutting of base. I have found that ordinary cracked dismetals which has been long recognized as adtillates containing the usual amounts of unsatvantageous in lard oil, sperm oil and the like; urated hydrocarbons can be combined with eleto make a satisfactory cutting oil from petroleum. mental sulphur in amounts such as to form stable In metal cutting work, lard oil has been the liquid compounds containing from 15 to 40 per 30 standard lubricant. It possesses the property oi. cent sulphur. The combination is efiected by wetting and sticking to the metal and thus lubriheating the cracked distillate with powdered sulcating the cutting tool and the cut metal. The phur to moderate temperatures above the meltlubricating and cooling action results in better ing point of sulphur until the added sulphur discutting work and in prolonging the use of the appears and by distilling oil unsulphurized hydrocutting tool without dulling or breaking. Other I carbons to leave a sulphurized residue. I have fatty oils of animal and vegetable origin have found that digesting a cracked-distillate with been used as cutting oils in place of lard oil. sulphur at temperatures rising from around Mineral lubricating oils generally do not give as 200 to about 300 F. and not exceeding 350 F.

good results as the fatty oils. It is desirable to be during 4 to 5 hours results in combination with 40 able to make satisfactory cutting oils from minthe oil of as much as 1'7 per cent by weight of eral oils, such as petroleum, and this has been sulphur, depending to a considerable extent the subject/of much research. upon the proportion of unsaturated hydrocar- Attempts have been made to produce cutting bans in the original distillate. I have further oils from petroleum bases by treating petroleum found that reduction by distillation of this sul- 45 in'various ways, such as chlorination and sulphurized oil at temperatures not exceeding 305 phurization to form oily or greasy bases from F. by about 65 per cent, results in a loss of less which cutting oils can be formed by dilution or than one per cent of the added sulphur, leaving compounding with lighter oils. The sulphurized a reduced liquid residue containing sulphur in mineral oils heretofore made are deficient as restable combination in a proportion as high as 50 I g I about 40 per cent of the total residue. It is also found that the reduced residue remains stable and homogeneous, losing upon continued standlng substantially no sulphur as such. The distillate separated from the sulphnrised unsatu rated hydrocarbons contains lea than 1 per cent sulphur and is available for the usual purification treatments to produce a marketable gasoline. This purified gasoline is substantially free from unsaturates and stabilized against oxidation and gum formation.

The heating digestion of the cracked distillate with sulphur is most advan carried out at atmospheric pressure in a still provided with a reflux condenser. The temperature is automatically regulated by the boiling point of the liquid mixture which slowly rises as the digestion proceeds. However, satisfactory sulphurization can be eiiected by heating under increased pressure with a gradually increasing temperature and separation of a low boiling oil fraction.

Temperatures below 300' P. maintained for several hours effect a stable combination of unsaturates with sulphur.

The exact composition of the sulphur compounds formed by the digestion of unsaturated hydrocarbons with elemental sulphur can not be stated. It appears probable that stable bydrocarbon sulphids are formed. The residue after separation of the unsulphurised low boiling distillate remains stable and homogeneous. For useas acuttingoilitis ormaybedilutedwith the common neutral refined oils. I have found that the sulphuriaed liquid residue made as described to contain 40 per cent sulphur, and diluted in 10'to 20partsofnmtraloiltoasulphur content ,of 2 to 4 per cent forms satisfactory cutting oils of suillciently high ilash and fire points and of low viscosity. The lubricating action of the diluted base in cutting work compares favorably with that of standard lard oil. Ithasshownitselftohesuperlortolardoil by actual tests. The diluted sulphurised oil may be mixed with lard oil to iinm-ove the action of the lard oil. It has the advantage of being cheaper than lard oil and a better lubricant for cutting metals. The high sulphur oil base may be added to kerosene and other petroleum distillates to make cutting oils for special purposes. It may also be compounded with various other cutting oils to improve their action as cutting lubricants.

In a specific embodiment of the present invention I have treated a heavy cracked distillate fraction made from a Venezuela crudeoil. The distillate fraction had the following P p rties:

A. P. I. gravity at 60 F 42 Iodine numberHanus (0.25 g. sample)- 89.5

One hundred parts of this heavy cracked distillate fraction containing unsaturated hydrocarbons in relatively large proportions were mixed with 18 parts by weight of powdered sulphur and the mixture was digested for five hours in a still heated by steam coils and provided with 1 therein.

of immiscible liquid at the bottom of the still." This layer of liquid sulphur disappeared after heating for about an hour longer and at the end of 5 hours digestion the liquid mass was homogeneous and dark in color. From parts by volume of the original distillate, 109 parts by volume of sulphurized distillate were obtained. Ifthissulphurizedoilispermittedtocoolan asphaltic material containing about 5 per cent of the sulphur used separates out from the solution and the decanted liquid contains about 16.7

per cent sulphur. Theasphaltic material so separating represents a small excess 01' sulflmr over that forming a stable liquid union with unsaturated hydrocarbons in the distillate.

After decanting, I have found it advantageous to leave the asphaltic residue in the still and;

proceed with the digestion of a second batch So doing, the reaction appears to be accelerated by the presence of the asphaltic residue. A small amount of residue is all that is required to accelerate sulphurization, and accordingly 'I remove some of the residue from time to time between successive runs.

The sulphurized distillate was then reduced by vacuum dry distillation at a pressure of 30 mm. of mercury and with the liquid temperature not exceeding 305 F. and a vapor temperature not over 240 F. Detectable amounts of hydrogen sulphid occurred in the distillation vapors and a sulphur balance on' the process indicated that not more than about 0.2 per cent of the total sulphur was lost as hydrogen sulphid. Distillation was continued under the stated temperature and pressure conditions until the sulphurised distillate was reduced 65 per cent in vohime. The 65 per cent distillate .contained 0.91 per cent sulphur. It responded well to the usual heavy acid treatment that is given to the heavy fraction of Venezuela cracked distillate; It is recovered and used for blending with gasoline.

The reduced residue was homogeneous. Upon standing at room temperature for several days a small proportion, about 1 per cent, of asphaltic material separated out but no sulphur, separated as such and no additional asphalt material was thrown out after further storage. The reduced liquid showed a sulphur content of 39.8 per cent by weight. It represented 37 percent by volume of the original cracked distillate and had the following properties:

Gravity; 'A. P. L.. 6.5 Specific gravity at 60 F 1.132 Flash point, 0. 0.: 'F 250. Fire point: F. 270. Viscosity, S. U. V.: 100' F 440. Viscosity, S. U. V.: 210 F 54.

The following table shows the of cutting oils formed by dilution of the sulphur- 3. In the method of claim 1, reducing the sulized base with various neutral refined oilsto phurized distillate at a temperature not exceedvarious percentages of sulphur content:

ing 305 F.

III

Diluent oil viscosity 155 E. U. V., 100" F.

203 S. U. V., 100 F. 13.3:1

255 S. U. V., 100 F. 10:1

380 F. 405 F. 450 F. 465 F.

The most conspicuous quality of the high sulphur cutting oil base is the moderate viscosity and ready miscibility in all proportions with petroleum lubricants and with fatty oils. In this respect the sulphurized cutting 011 base containing from 15 to per cent sulphur is a distinctly superior product. The high sulphur content of this cutting oil base, which permits of a dilution of as much as 20'fold in order to make a cutting oil, makes it possible to add it to any oil having the desired physical properties without materially altering these properties. Cutting oils so made are low in cost and superior to lard oil.

What I claim is: i

1. A method of making a stable cutting oil base of high sulphur content from petroleum oil which comprises heating a cracked distillate with sulphur at temperatures under 350 F. until the sulphur disappears as such and reducing the sulphurized distillate by distillation of unsulphurized hydrocarbons.

2. In the method 01' claim 1, heating under reflux condensation at atmospheric pressure prior to reduction.

4. A method of making a stable cutting oil base of high sulphur content which comprises subjecting a cracked naphtha distillate and sulphur to a temperature above the melting point of the sulphur but not exceeding 350 F. until a product containing at least 15 per cent of stable compounds of sulphur and hydrocarbon constituents present is obtained, and then subjecting the product to controlled partial distillation at temperatures somewhat below the end boiling point of the original distillate, whereby unsulphurized constituents are removed leaving a residue containing a substantially increased proportion of stable sulphur compounds and suitable for use as a cutting oil base.

5. A cutting oil base comprising a residue from the distillation of a sulphurized cracked petroleum naphtha, containing stable compounds of sulphur and hydrocarbon constituents of said naphtha, the sulphur content being from 15 to 40 per cent by weight of the cutting oil base.

IRVING MUSKAT. 

